B. Emission standards:

1. (1) The owner or operator of a portable or stationary natural gas-fired spark ignition engine, compression ignition engine, or natural gas-fired combustion turbine shall ensure compliance with the emission standards by the dates specified in Subsection B of 20.2.50.113 NMAC, except as otherwise specified under an Alternative Compliance Plan approved pursuant to Paragraph (10) of Subsection B of 20.2.50.113 NMAC or alternative emissions standards approved pursuant to Paragraph (11) of Subsection B of 20.2.50.113 NMAC.

2. (2) The owner or operator of an existing natural gas-fired spark ignition engine shall complete an inventory of all existing engines subject to this Part by January 1, 2023, and shall prepare a schedule to ensure that each existing engine does not exceed the emission standards in table 1 of Paragraph (2) of Subsection B of 20.2.50.113 NMAC as follows, except as otherwise specified under an Alternative Compliance Plan (ACP) approved pursuant to Paragraph (10) of Subsection B of 20.2.50.113 NMAC or alternative emissions standards approved pursuant to Paragraph (11) of Subsection B of 20.2.50.113 NMAC:

   1. (a) by January 1, 2025, the owner or operator shall ensure at least thirty percent of the company’s existing engines meet the emission standards.
   2. (b) by January 1, 2027, the owner or operator shall ensure at least an additional thirty-five percent of the company’s existing engines meet the emission standards.
   3. (c) by January 1, 2029, the owner or operator shall ensure that the remaining thirty-five percent of the company’s existing engines meet the emission standards.

   4. (d) in lieu of meeting the emission standards for an existing natural gas-fired spark ignition engine, an owner or operator may reduce the annual hours of operation of an engine such that the annual PTE of NOx and VOC emissions are reduced to achieve an equivalent allowable ton per year emission reduction as set forth in table 1 of Paragraph (2) of Subsection B of 20.2.50.113 NMAC, or by at least ninety-five percent per year.

      Table 1 - EMISSION STANDARDS FOR EXISTING NATURAL GAS-FIRED SPARK IGNITION ENGINES

      Engine Type Rated bhp NO_x CO NMNEHC (as propane) 2 Stroke Lean Burn >1,000 3.0 g/bhp-hr 0.60 g/bhp-hr 0.70 g/bhp-hr 4-Stroke Lean Burn >1,000 bhp and <1,775 bhp 2.0 g/bhp-hr 0.60 g/bhp-hr 0.70 g/bhp-hr 4-Stroke Lean Burn ≥1,775 bhp 0.5 g/bhp-hr 0.60 g/bhp-hr 0.70 g/bhp-hr Rich Burn >1,000 bhp 0.5 g/bhp-hr 0.60 g/bhp-hr 0.70 g/bhp-hr

      Engine Type

      Rated bhp

      NO_x

      CO

      NMNEHC (as propane)

      2 Stroke Lean Burn

      >1,000

      3.0 g/bhp-hr

      0.60 g/bhp-hr

      0.70 g/bhp-hr

      4-Stroke Lean Burn

      >1,000 bhp and <1,775 bhp

      2.0 g/bhp-hr

      0.60 g/bhp-hr

      0.70 g/bhp-hr

      4-Stroke Lean Burn

      ≥1,775 bhp

      0.5 g/bhp-hr

      0.60 g/bhp-hr

      0.70 g/bhp-hr

      Rich Burn

      >1,000 bhp

      0.5 g/bhp-hr

      0.60 g/bhp-hr

      0.70 g/bhp-hr

3. (3) The owner or operator of a new natural gas-fired spark ignition engine shall ensure the engine does not exceed the emission standards in table 2 of Paragraph (3) of Subsection B of 20.2.50.113 NMAC upon startup.

   Table 2 - EMISSION STANDARDS FOR NEW NATURAL GAS-FIRED SPARK IGNITION ENGINES

   Engine Type Rated bhp NO_x CO NMNEHC (as propane) Lean-burn > 500 and < 1875 0.50 g/bhp-hr 0.60 g/bhp-hr 0.70 g/bhp-hr Lean-burn ≥ 1875 0.30 g/bhp-hr 0.60 g/bhp-hr 0.70 g/bhp-hr Rich-burn >500 0.50 g/bhp-hr 0.60 g/bhp-hr 0.70 g/bhp-hr

   Engine Type

   Rated bhp

   NO_x

   CO

   NMNEHC (as propane)

   Lean-burn

   > 500 and < 1875

   0.50 g/bhp-hr

   0.60 g/bhp-hr

   0.70 g/bhp-hr

   Lean-burn

   ≥ 1875

   0.30 g/bhp-hr

   0.60 g/bhp-hr

   0.70 g/bhp-hr

   Rich-burn

   >500

   0.50 g/bhp-hr

   0.60 g/bhp-hr

   0.70 g/bhp-hr

4. (4) The owner or operator of a natural gas-fired spark ignition engine with NO_x emission control technology that uses ammonia or urea as a reagent shall ensure that the exhaust ammonia slip is limited to 10 ppmvd or less, corrected to fifteen percent oxygen.

5. (5) The owner or operator of a compression ignition engine shall ensure compliance with the following emission standards:

   1. (a) a new portable or stationary compression ignition engine with a maximum design power output equal to or greater than 500 horsepower that is not subject to the emission standards under Subparagraph (b) of Paragraph (5) of Subsection B of 20.2.50.113 NMAC shall limit NO_x emissions to not more than nine g/bhp-hr upon startup.
   2. (b) a stationary compression ignition engine that is subject to and complying with Subpart IIII of 40 CFR Part 60, Standards of Performance for Stationary Compression Ignition Internal Combustion Engines, is not subject to the requirements of Subparagraph (a) of Paragraph (5) of Subsection B of 20.2.50.113 NMAC.
6. (6) The owner or operator of a portable or stationary compression ignition engine with NO_x emission control technology that uses ammonia or urea as a reagent shall ensure that the exhaust ammonia slip is limited to 10 ppmvd or less, corrected to fifteen percent oxygen.

7. (7) The owner or operator of a stationary natural gas-fired combustion turbine with a maximum design rating equal to or greater than 1,000 bhp shall comply with the applicable emission standards for an existing, new, or reconstructed turbine listed in table 3 of Paragraph (7) of Subsection B of 20.2.50.113 NMAC: The owner or operator of an existing stationary natural gas-fired combustion turbine shall complete an inventory of all existing turbines subject to Part 50 by July 1, 2023, and shall prepare a schedule to ensure that each subject existing turbine does not exceed the emission standards in table 3 of Paragraph (7) of Subsection B of 20.2.50.113 NMAC as follows, except as otherwise specified under an Alternative Compliance Plan approved pursuant to Paragraph (10) of Subsection B of 20.2.50.113 NMAC or alternative emissions standards approved pursuant to Paragraph (11) of Subsection B of 20.2.50.113 NMAC:

   1. (a) by January 1, 2024, the owner or operator shall ensure at least thirty percent of the company’s existing turbines meet the emission standards.

(b) by January 1, 2026, the owner or operator shall ensure at least an additional thirty-five percent of the company’s existing turbines meet the emission standards.

1. (c) by January 1, 2028, the owner or operator shall ensure that the remaining thirty-five percent of the company’s existing turbines meet the emission standards.

2. (d) in lieu of meeting the emission standards for an existing stationary natural gas-fired combustion turbine, an owner or operator may reduce the annual hours of operation of a turbine such that the annual PTE of NOx and VOC emissions are reduced to achieve an equivalent allowable ton per year emission reduction as set forth in table 3 of Paragraph (7) of Subsection B of 20.2.50.113 NMAC, or by at least ninety-five percent per year.

   Table 3 - EMISSION STANDARDS FOR STATIONARY COMBUSTION TURBINES

   For each applicable existing natural gas-fired combustion turbine, the owner or operator shall ensure the turbine does not exceed the following emission standards no later than the schedule set forth in Paragraph (7)(a) of Subsection B of 20.2.50.113 NMAC: Turbine Rating (bhp) NO_x (ppmvd @15% O₂) CO (ppmvd @ 15% O₂) NMNEHC (as propane, ppmvd @15% O₂) ≥1,000 and <4,100 150 50 9 ≥4,100 and <15,000 50 50 9 ≥15,000 50 50 or 93% reduction 5 or 50% reduction For each applicable new natural gas-fired combustion turbine, the owner or operator shall ensure the turbine does not exceed the following emission standards upon startup: Turbine Rating (bhp) NO_x (ppmvd @15% O₂) CO (ppmvd @ 15% O₂) NMNEHC (as propane, ppmvd @15% O₂) ≥1,000 and <4,000 100 25 9 ≥4,000 and <15,900 15 10 9 ≥15,900 9.0 Uncontrolled or 2.0 with Control 10 Uncontrolled or 1.8 with Control 5

   For each applicable existing natural gas-fired combustion turbine, the owner or operator shall ensure the turbine does not exceed the following emission standards no later than the schedule set forth in Paragraph (7)(a) of Subsection B of 20.2.50.113 NMAC:

   Turbine Rating (bhp)

   NO_x (ppmvd @15% O₂)

   CO (ppmvd @ 15% O₂)

   NMNEHC (as propane, ppmvd @15% O₂)

   ≥1,000 and <4,100

   150

   50

   9

   ≥4,100 and <15,000

   50

   50

   9

   ≥15,000

   50

   50 or 93% reduction

   5 or 50% reduction

   For each applicable new natural gas-fired combustion turbine, the owner or operator shall ensure the turbine does not exceed the following emission standards upon startup:

   Turbine Rating (bhp)

   NO_x (ppmvd @15% O₂)

   CO (ppmvd @ 15% O₂)

   NMNEHC (as propane, ppmvd @15% O₂)

   ≥1,000 and <4,000

   100

   25

   9

   ≥4,000 and <15,900

   15

   10

   9

   ≥15,900

   9.0 Uncontrolled or

   2.0 with Control

   10 Uncontrolled or

   1.8 with Control

   5

3. (8) The owner or operator of a stationary natural gas-fired combustion turbine with NO_x emission control technology that uses ammonia or urea as a reagent shall ensure that the exhaust ammonia slip is limited to 10 ppmvd or less, corrected to fifteen percent oxygen.
4. (9) The owner or operator of an emergency use engine as defined by 40 C.F.R. §§ 60.4211, 60.4243, or 63.6675 is not subject to the emissions standards in this Part but shall be equipped with a non-resettable hour meter to monitor and record any hours of operation.

5. (10) In lieu of complying with the emission standards for individual engines and turbines established in Subsection B of 20.2.50.113 NMAC, an owner or operator may elect to comply with the emission standards through an Alternative Compliance Plan (ACP) approved by the department. An ACP must include the list of engines or turbines subject to the ACP, and a demonstration that the total allowable emissions for the engines or turbines subject to the ACP will not exceed the total allowable emissions under the emission standards of this Part. Prior to submitting a proposed ACP to the Department, the owner or operator shall comply with the following requirements in the order listed:

   1. (a) The owner or operator shall contract with an independent third-party engineering or consulting firm to conduct a technical and regulatory review of the ACP proposal. The selected firm shall review the proposal to determine if it meets the requirements of this Part, and shall prepare and certify an evaluation of the proposed ACP indicting whether the ACP proposal adheres to the requirements of this Part.
   2. (b) Following the independent third-party review, the owner or operator shall provide the ACP, along with the third-party evaluation and findings, to the department for posting on the department’s website. The department shall post the ACP and the third-party review within 15 days of receipt.
   3. (c) Following posting by the department, the owner or operator shall publish a notice in a newspaper of general circulation announcing the ACP proposal, the dates it will be available for review and comment by the public, and information on how and where to submit comments. The dates specified in the public notice must provide for a thirty-day comment period.
   4. (d) Following the close of the thirty-day notice and comment period, the department shall send the comments submitted on the ACP proposal and findings to the owner or operator. The owner or operator shall provide written responses to all comments to the department.

(e) Following receipt of the owner or operator’s responses to comments received during the thirty-day comment period, the department shall make a determination whether to approve or deny the ACP proposal within 90 days. The department shall approve an ACP that meets the requirements of this Part, unless the department determines that the total allowable emissions under the ACP exceed the total allowable emissions under the emission standards of 20.2.50.113 NMAC. If approved by the department, the emission reductions and associated emission limits for the affected engines or turbines shall become enforceable terms under this Part.

1. (11) The owner or operator may submit a request for alternative emission standards for a specific engine or turbine based on technical impracticability or economic infeasibility. The owner or operator is not required to submit an ACP proposal under Paragraph (10) of Subsection B of 20.2.50.113 NMAC prior to submission of a request for alternative emissions standards under this Paragraph (11), provided that the owner or operator satisfies Subparagraph (b) of Paragraph (11) of Subsection B of 20.2.50.113 NMAC, below. To qualify for an alternative emission standard, an owner or operator must comply with the following requirements:

   1. (a) Prepare a reasonable demonstration detailing why it is not technically practicable or economically feasible for the individual engine or turbine to achieve the emissions standards in table 1 of Paragraph (2) of Subsection B of 20.2.50.113 NMAC or table 3 of Paragraph (7) of Subsection B of 20.2.50.113 NMAC, as applicable;
   2. (b) Prepare a demonstration detailing why emissions from the individual engine or turbine cannot be addressed through an ACP in a technically practicable or economically feasible manner;
   3. (c) Prepare a technical analysis for the affected engine or turbine specifying the emission reductions that can be achieved through other means, such as combustion modifications or capacity limitations. The technical analysis shall include an analysis of any previous modifications of the source and a determination whether such modifications meet the definition of a reconstructed source, such that the source should be considered a new source under federal regulations. The analysis shall include a certification that the modifications to the source are not in violation of any state or federal air quality regulation; and
   4. (d) Fulfill the requirements of Subparagraphs (a) through (c) of Paragraph (10) of Subsection B of 20.2.50.113 NMAC.
   5. (e) Following the close of the thirty-day notice and comment period, the department shall send the comments submitted on the alternative emission standards and findings to the owner or operator. The owner or operator shall provide written responses to all comments to the department.
   6. (f) Following receipt of the owner or operator’s responses to comments received during the thirty-day comment period, the department shall make a determination whether to approve or deny the alternative emission standards within 90 days. If approved by the department, the emission reductions and alternative emission standards for the affected engine or turbine shall become enforceable terms under this Part.
   7. (g) If approved by the department, the emissions reductions and alternative standards for the affected engine or turbine shall become enforceable terms under this Part.
2. (12) A short-term replacement engine may be substituted for any engine subject to Section 20.2.50.113 NMAC consistent with any applicable air quality permit containing allowances for short term replacement engines, including but not limited to New Source Review and General Construction Permits issued under 20.2.72 NMAC. A short-term replacement engine is not considered a “new” engine for purposes of this Part unless the engine it replaces is a “new” engine within the meaning of this Part. The reinstallation of the existing engine following removal of the short-term replacement engine is not considered a “new” engine under this Part unless the engine was “new” prior to the temporary replacement.

C. Monitoring requirements:

1. (1) Maintenance and repair for a spark ignition engine, compression ignition engine, and stationary combustion turbine shall meet the manufacturer recommended maintenance schedule as defined in 20.2.50.112 NMAC.
2. (2) Maintenance conducted consistent with an applicable NSPS or NESHAP requirement shall be deemed to be in compliance with Paragraph (1) of Subsection (C) of 20.2.50.113 NMAC.
3. (3) Catalytic converters (oxidative, selective, and non-selective) and AFR controllers shall be inspected and maintained according to manufacturer specifications as defined in 20.2.50.112 NMAC, and shall include replacement of oxygen sensors as necessary for oxygen-based controllers. During periods of catalytic converter or AFR controller maintenance, the owner or operator shall shut down the engine or turbine until the catalytic converter or AFR controller can be replaced with a functionally equivalent spare to allow the engine or turbine to return to operation.

4. (4) For equipment operated for 500 hours per year or more, compliance with the emission standards in Subsection B of 20.2.50.113 NMAC shall be demonstrated within 180 days of the effective date applicable to the source as defined by Paragraphs (2) and (7) of Subsection B of this Section or, if installed more than 180 days after the effective date, within 60 days after achieving the maximum production rate at which the source will be operated, but not later than 180 days after initial startup of such source. Compliance with the applicable emission standards shall be demonstrated by performing an initial emission test for NOx and VOC, as defined in 40 CFR 51.100(s) using U.S. EPA reference methods or ASTM D6348. Periodic monitoring shall be conducted annually to demonstrate compliance with the allowable emission standards and may be demonstrated utilizing a portable analyzer or EPA reference methods. For units with g/hp-hr emission standards, the engine load shall be calculated using the following equations:

   Where: LVH = lower heating value, btu/scf, or btu/gal, as appropriate; and

   BSFC = brake specific fuel consumption

   If the manufacturer’s rated BSFC is not available, an operator may use an alternative load calculation methodology based on available data.

(a) emissions testing shall be conducted within 10 percent of 100 percent peak (or the highest achievable) load. The load and the parameters used to calculate it shall be recorded to document operating conditions at the time of testing and shall be included with the test report.

1. (b) emissions testing utilizing a portable analyzer shall be conducted in accordance with the requirements of the current version of ASTM D6522. If a portable analyzer has met a previously approved department criterion, the analyzer may be operated in accordance with that criterion until it is replaced.
2. (c) the default time period for a test run shall be at least 20 minutes.
3. (d) an emissions test shall consist of three separate runs, with the arithmetic mean of the results from the three runs used to determine compliance with the applicable emission standard.
4. (e) during emissions tests, pollutant and diluent concentration shall be monitored and recorded. Fuel flow rate shall be monitored and recorded if stack gas flow rate is determined utilizing U.S. EPA reference method 19. This information shall be included with the periodic test report.
5. (f) stack gas flow rate shall be calculated in accordance with U.S. EPA reference method 19 utilizing fuel flow rate (scf) determined by a dedicated fuel flow meter and fuel heating value (Btu/scf). The owner or operator shall provide a contemporaneous fuel gas analysis (preferably on the day of the test, but no earlier than three months before the test date) and a recent fuel flow meter calibration certificate (within the most recent quarter) with the final test report. Alternatively, stack gas flow rate may be determined by using U.S. EPA reference methods 1 through 4 or through the use of manufacturer provided fuel consumption rates.
6. (g) upon request by the department, an owner or operator shall submit a notification and protocol for an initial or annual emissions test.
7. (h) emissions testing shall be conducted at least once per calendar year. Emission testing required by Subparts GG, IIII, JJJJ, or KKKK of 40 CFR 60, or Subpart ZZZZ of 40 CFR 63, may be used to satisfy the emissions testing requirements if it meets the requirements of 20.2.50.113 NMAC and is completed at least once per calendar year.
8. (i) The results of emissions testing demonstrating compliance with the emission standard for CO may be used as a surrogate to demonstrate compliance with the emission standard for NMNEHC.
9. (5) The owner or operator of equipment operated less than 500 hours per year shall monitor the hours of operation using a non-resettable hour meter and shall test the unit at least once per 8760 hours of operation in accordance with the emissions testing requirements in Paragraph (4) of Subsection C of 20.2.50.113 NMAC.
10. (6) An owner or operator of an emergency use engine as defined by 40 C.F.R. §§ 60.4211, 60.4243, or 63.6675 shall monitor the hours of operation by a non-resettable hour meter.
11. (7) An owner or operator limiting the annual operating hours of an engine or turbine to meet the requirements of Paragraph (2) or (7) of Subsection B of 20.2.50.113 NMAC shall monitor the hours of operation by a non-resettable hour meter.
12. (8) Prior to any monitoring, testing, inspection, or maintenance of an engine or turbine, the owner or operator shall date and time stamp the event, and the monitoring data entry shall be made in accordance with the requirements of 20.2.50.112 and 113 NMAC.

D. Recordkeeping requirements:

1. (1) The owner or operator of a spark ignition engine, compression ignition engine, or stationary combustion turbine shall maintain a record in accordance with 20.2.50.112 NMAC for the engine or turbine. The record shall include:

(a) the make, model, serial number, and unique identification number for the engine or turbine;

1. (b) location of the source (latitude and longitude);
2. (c) a copy of the engine, turbine, or control device manufacturer recommended maintenance and repair schedule as defined in 20.2.50.112 NMAC; and

3. (d) all inspection, maintenance, or repair activity on the engine, turbine, and control device, including:

   1. (i) the date and time stamp(s), including GPS of the location, of an inspection, maintenance, or repair;
   2. (ii) the date a subsequent analysis was performed (if applicable);
   3. (iii) the name of the person(s) conducting the inspection, maintenance or repair;
   4. (iv) a description of the physical condition of the equipment as found during the inspection;
   5. (v) a description of maintenance or repair conducted; and
   6. (vi) the results of the inspection and any required corrective actions.

4. (2) The owner or operator of a spark ignition engine, compression ignition engine, or stationary combustion turbine shall maintain records of initial and annual emissions testing for the engine or turbine for a period of five years. The records shall include:

   1. (a) make, model, and serial number for the tested engine or turbine;
   2. (b) the date and time stamp(s), including GPS of the location, of any monitoring event, including sampling or measurements;
   3. (c) date analyses were performed;
   4. (d) name of the person(s) and the qualified entity that performed the analyses;
   5. (e) analytical or test methods used;
   6. (f) results of analyses or tests;
   7. (g) calculated emissions of NOx and VOC in lb/hr and tpy; and
   8. (h) operating conditions at the time of sampling or measurement.
5. (3) The owner or operator of an emergency use engine as defined by 40 C.F.R. §§ 60.4211, 60.4243, or 63.6675 shall record the total annual hours of operation as recorded by the non-resettable hour meter.
6. (4) The owner or operator limiting the annual operating hours of an engine or turbine to meet the requirements of Paragraph (2) or (7) of Subsection B of 20.2.50.113 NMAC shall record the hours of operation by a non-resettable hour meter. The owner or operator shall calculate and record the annual NOx and VOC emission calculation, based on the engine or turbine’s actual hours of operation, to demonstrate that an equivalent allowable ton per year emission reduction as set forth in table 1 or table 3 of Paragraph (2) or (7) of Subsection B of 20.2.50.113 NMAC, or the ninety-five percent emission reduction requirement is met.

E. Reporting requirements: The owner or operator shall comply with the reporting requirements in 20.2.50.112 NMAC.

[20.2.50.113 NM–C - N, 08/05/2022]